(function () {
    function forEach(arr, f) {
        for (var i = 0, e = arr.length; i < e; ++i) f(arr[i]);
    }

    function arrayContains(arr, item) {
        if (!Array.prototype.indexOf) {
            var i = arr.length;
            while (i--) {
                if (arr[i] === item) {
                    return true;
                }
            }
            return false;
        }
        return arr.indexOf(item) != -1;
    }

    function scriptHint(editor, keywords, getToken) {
        // Find the token at the cursor
        var cur = editor.getCursor(), token = getToken(editor, cur), tprop = token;
        // If it's not a 'word-style' token, ignore the token.
        if (!/^[\w$_]*$/.test(token.string)) {
            token = tprop = {
                start: cur.ch, end: cur.ch, string: "", state: token.state,
                className: token.string == "." ? "property" : null
            };
        }
        // If it is a property, find out what it is a property of.
        while (tprop.className == "property") {
            tprop = getToken(editor, {line: cur.line, ch: tprop.start});
            if (tprop.string != ".") return;
            tprop = getToken(editor, {line: cur.line, ch: tprop.start});
            if (tprop.string == ')') {
                var level = 1;
                do {
                    tprop = getToken(editor, {line: cur.line, ch: tprop.start});
                    switch (tprop.string) {
                        case ')':
                            level++;
                            break;
                        case '(':
                            level--;
                            break;
                        default:
                            break;
                    }
                } while (level > 0);
                tprop = getToken(editor, {line: cur.line, ch: tprop.start});
                if (tprop.className == 'variable')
                    tprop.className = 'function';
                else return; // no clue
            }
            if (!context) var context = [];
            context.push(tprop);
        }
        return {
            list: getCompletions(token, context, keywords),
            from: {line: cur.line, ch: token.start},
            to: {line: cur.line, ch: token.end}
        };
    }

    CodeMirror.javascriptHint = function (editor) {
        return scriptHint(editor, javascriptKeywords,
            function (e, cur) {
                return e.getTokenAt(cur);
            });
    };

    function getCoffeeScriptToken(editor, cur) {
        // This getToken, it is for coffeescript, imitates the behavior of
        // getTokenAt method in javascript.js, that is, returning "property"
        // type and treat "." as indepenent token.
        var token = editor.getTokenAt(cur);
        if (cur.ch == token.start + 1 && token.string.charAt(0) == '.') {
            token.end = token.start;
            token.string = '.';
            token.className = "property";
        }
        else if (/^\.[\w$_]*$/.test(token.string)) {
            token.className = "property";
            token.start++;
            token.string = token.string.replace(/\./, '');
        }
        return token;
    }

    CodeMirror.coffeescriptHint = function (editor) {
        return scriptHint(editor, coffeescriptKeywords, getCoffeeScriptToken);
    };

    var stringProps = ("charAt charCodeAt indexOf lastIndexOf substring substr slice trim trimLeft trimRight " +
    "toUpperCase toLowerCase split concat match replace search").split(" ");
    var arrayProps = ("length concat join splice push pop shift unshift slice reverse sort indexOf " +
    "lastIndexOf every some filter forEach map reduce reduceRight ").split(" ");
    var funcProps = "prototype apply call bind".split(" ");
    var javascriptKeywords = ("break case catch continue debugger default delete do else false finally for function " +
    "if in instanceof new null return switch throw true try typeof var void while with").split(" ");
    var coffeescriptKeywords = ("and break catch class continue delete do else extends false finally for " +
    "if in instanceof isnt new no not null of off on or return switch then throw true try typeof until void while with yes").split(" ");

    function getCompletions(token, context, keywords) {
        var found = [], start = token.string;

        function maybeAdd(str) {
            if (str.indexOf(start) == 0 && !arrayContains(found, str)) found.push(str);
        }

        function gatherCompletions(obj) {
            if (typeof obj == "string") forEach(stringProps, maybeAdd);
            else if (obj instanceof Array) forEach(arrayProps, maybeAdd);
            else if (obj instanceof Function) forEach(funcProps, maybeAdd);
            for (var name in obj) maybeAdd(name);
        }

        if (context) {
            // If this is a property, see if it belongs to some object we can
            // find in the current environment.
            var obj = context.pop(), base;
            if (obj.className == "variable")
                base = window[obj.string];
            else if (obj.className == "string")
                base = "";
            else if (obj.className == "atom")
                base = 1;
            else if (obj.className == "function") {
                if (window.jQuery != null && (obj.string == '$' || obj.string == 'jQuery') &&
                    (typeof window.jQuery == 'function'))
                    base = window.jQuery();
                else if (window._ != null && (obj.string == '_') && (typeof window._ == 'function'))
                    base = window._();
            }
            while (base != null && context.length)
                base = base[context.pop().string];
            if (base != null) gatherCompletions(base);
        }
        else {
            // If not, just look in the window object and any local scope
            // (reading into JS mode internals to get at the local variables)
            for (var v = token.state.localVars; v; v = v.next) maybeAdd(v.name);
            gatherCompletions(window);
            forEach(keywords, maybeAdd);
        }
        return found;
    }
})();
